Buttonhole-sewing machine



Sept. 21 1926,

.E- B. ALLEN BUTTONHOLE SEWING MACHINE ile'd Jui 5. 1925 9 Sheets' sheet 1 INVENTOR W fl mu. 7

A ORNEY WITNESSESv n x m w .2 u M m 0 w l an 6 V w m m MW E m w G M 9 m H QQ H W E FFEEF N L w w m m w L G m w m B E J L d E W m w F m U B Ill INVENTOR A ae By WITNESSES ATTORNEY Sept. 21 1926. 1,600,206

E. B. ALLEN BUTTONHOLE SEWING MACHINE 9 Sheets-Sheet 5 Filed July 5. 1923 INVENTOR M flaw, WITNESSES BY ATTORNEY Sept. 21 1926.

E. B. ALLEN BUTTONHOLE SEWING MACHINE Filed July 5. 1923 9 Sheets-She'et 4 ruL \NVENTOR QM Wk ATTORNEY WITNESSES E. B. ALLEN BUTTONHOLE SEWING MA CHI NE F d y 1923 9 Sheets-Sheet 5 n\mnnmumimiiiii ATTORNEY Sept. 21 1926.

I E. B. ALLEN BUTTONHOLE SEWING MACHINE 9 Sheets-Shet 6 Filed July 5. 1923 INVENTOR mfl W WITNESSES BY fi jflaw. QM ATTORNEY E. B. ALLEN BUTTONHOLE SEWING MACHINE Sept. 21 1926.

ATTORNEY WITNESSES- Sept. 21 1926.

E. B. ALLEN BUTTONHOLE SEWING MACHINE Filed July 5. 1923 9 Sheets-Sheet 8 II-I /,////1////// VENTOR M (Q. QIQL BY ATTORNEY Sept. 21 1926. I

E. B. ALLEN BUTTONHOLE SEWING MACHINE 9 Sheets-Sheet 9 Filed July 5. 1923- INVENTOR M a m.

WITNESSES By WfleW 1 ATTORNEY Patented Sept. 21, 1926.1

UNITED STATES PATENT OFFICE.

EDWARD B. ALLEN, OF NEWTOWN, CONNECTICUT, ASSIGNOR TO THE SINGER MANU- v FACTURING COMPANY, OF ELIZABETH, NEW JERSEY, A CORPORATION OF NEW JERSEY.

BUTTONHOLE-SEWIN G MACHINE.

Application filed July 5, 1923. Serial No. 649,440.

This invention relates to automatic buttonhole sewing machines and has for an;

object to provide a high-speed machine particularly adapted for cloth work,whereby 6 a maximum production of stitched buttonholes may be obtained with a minimum of effort on the part of the operator; the buttonholesbeing finished when removed from the machine and requiring no subsequent hand trimming operations. Another object of the invention is to provide the machine with an under thread and cord trimmer which is independent of the buttonhole cut- 1 ting mechanism and hence applicable to before or after the sewing period. Another object of the invention is to provide simpll fie'd means for freeing the under thread 2 needle-loop customarily retained thereby.

which the quality of the finished button-' holes is more important than the quantity of buttonholes produced per machine. The

that it embodies stitch-forming mechanism of the so-called I. B. H'. (improved but: tonhole) type wherein an upper reciprocat- 4 ing and laterally jogging needle makes two forming cycle. It isimpracticable to operate stitch-forming mechanism of this type at speeds easily attained by stitch forining mechanism of the H & H type represented in my Patent No. 1,162,207, of November 30, 1915. In stitch-formingmechanism, of the H & H type, a lower curved slit-stitch needle cooperates with an upper strai ht depth-stitch needle; the latter making ut one complete reciprocation per stitch-forming cycle. p

The machine of my said Patent No.

length throughout the series. When sewing machines which cut the buttonhole either.

mechanism or loop-taker from the last speed of the machine of my said copending application is limited because of, the fact' complete reciprocations for each stitch-' comprises the novel'combinations of parts 1,162,207, is intended primarily for leather work, such as the sewing of a. series of buttonholes in a shoe upper and, for this work,

an under thread and cord trimmer is not required, as the buttonholes are stronger if the cord bridges the spaces between the buttonholes and extends in one continuous 60 buttonholes in cloth, however, it is desirable that the cord and sewing threads be trimmed close to the last stitch so that each individual buttonhole will have a finished appearance on both sides when removed from the machine and will not have to be retrimmed by hand. 7

To the attainment of the ends in view I have reorganized the machine of my said copending application building into itstitch-forming mechanism of the. upper straight needle and lower curved needle type. The under thread and cord-trimmer is arranged to be operated by a cam on the. rapid feed-shaft of the machine and is inde pendent of the buttonhole cutting mechanism. An upper-thread trimmer is arranged to sever the needle-thread at the end of the sewing period and means are provided for thereafter shifting the work-holder away .from the stitch-forming mechanism to draw the last, needle-loop clear of the loop-taker and also to draw off safe lengths of. under thread and cord prior to the action of the under thread and cord-trimmer. The purl of the overlying stitchesof a fly-bar button hole is controlled by automatic mechanism operated by the rapid feed-shaft for increasing the tension on the under thread, during the sewing of said overlying stitches, whereby the purl will be pulled over to the curvedneedle punctures and give the fin-. ished buttonhole and even, flat and desirable appearance." The present invention further anddetails of construction "hereinafter described and particularly pointed .out in the appended claims.

In the accompanying drawings, Fig. 1 is a right-side elevation of a buttonhole sews 10o ing machine embodying the invention; the parts being in their respective positions 00- cupiedwhen the machine is at rest. Fig. 2 is a left-side ,elevation of the-machine.

Fig. 3 is a front elevation of the machine with the work-supporting plates in section. Fig. 4 is a horizontal section through the bracket-arm standard of the machine and with the work-clamp removed toshow in plan certain mechanism within the machine bed. Fig. 5 is a fragmentary rear end elevation of the machine. Fig. 6 is a transverse section through the machine bed showing the rapid-feed shaft and certain details of the automatic clutch-mechanism for connecting it to its rapid-drivingshaft Fi 71 is a top plan view of the left-hand wor -c lamping lever and its fulcrum block. Figi 8 isan inner side elevation of the same. Fig. 9 is a fragmentary front elevation showing in dotted and full lines theunder thread and cord-cutterv in retracted and operative posi-. tions, respectively. Fig. 10 is a fragmentary plan view of the lower work-supporting plates of the work-clamp. .Fig.'l1 is a sectional view through the upper threadtension and its support. Fig.- 12-is a fragmentary side elevation, partly in section, of. the mechanism for-increasing the" tension of the underthread tension device. Fig. 13 is a detailperspective view of the under-thread tension-modifying lever. Figs. 14 to 19 inelusive are views illustrating the relative positions of the parts adjacent the sewing point at different Iperiods of a 'buttonholeproducing cycle. ig. 20 is a plan view of the corded side of a finished buttonhole, as removed from the machine and Fig. 21 is a fragmentary elevation within the machine bed showing l certain details of the clutchcontrolling mechanism for the rapid-feed shaft. p

In the preferred embodiment of the invention, as illustrated, the machine is con structed with a frame comprising a hollow rectangular bed 1 from one end of which rises the standard 2 of the. bracket-arm .3 terminating in the head 4.

The stitch-forming mechanism is constructed substantially in accordance with. the disclosure of my said Patent 0. 1.162,207 and the Allen & Crosby Patent No. 1,275,999. of August 20, 1918, and includes the upper eye-pointed straight needle 5 carried bythe needle-bar 6 journaled Jin the head 4 for the usual reciprocatory and axial turning movements. The needle 5 makes depth-stitches only and cooperates with a lower curved needle 7' and loop-taker 8 whichlatterseizes a depth-stitch loop from the needle 5 and resents it for entry by the curved needle 7; the latter carrying a loop of under thread through the loop of upper thread and over the edge of thebuttonhole-slit. positioning said under thread loop at the upper side of the work for entry by,the upper needle in its next descent.

Thus, the'upper needle makes but one complete reciprocation ,for each stitch-forming cycle and the mechanism operates smoothly at speeds much higher than are practicable with stitch-forming mechanism of the be operated by the upper or needle-bar operating shaft 9 geared at 10 to be driven from the vertical shaft 1-1 at double the speed of the latter.

The shaft 11 is geared at 12 to be driven by and at the same speed as the main sewing shaft 13.

The curved needle 7 and loop-taker 8 are .mounted on the rotary turret '14 and are-connected in the usual manner, substantially as represented in said Allen & Crosby patent, to beoperated bythe looper-operating shaft 15 which is geared at 16 to. be driven by the main sewing shaft I3 at dou blc the speed of the latter. The needlebar operating shaft 9 and the looper operating shaft 15 are thus driven at the same speed. which is double 'the speed of the main sewing shaft- 13. During the sewing, the needle-bar 6 and turret 14 are turned by the .usual connections with the feedwheel 17 to lay the stitches radially around the eyelet-end of the buttonhole. After the sewing is completed the parts are reversely turned to initial position. The needles oper; ate through the'crescent-shaped aperture in the usual needle-throat or button 18 carried by the turret 14; the button 18 being apertured as usual to guide the stay-cord s.

. The work-holder is of the usual construction substantially, represented in, my said reissued patent. It is adapted to move both initial or buttonhole cutting position. The

work-holder comprises the lower worksu'pporting plates 19, separable to spread the buttonhole and the upper clamping feet 20 which .are'carriedby the usual clamplevers 21 operated by the connected rockshaft sections 22. one of which. Fig. -1, car- Iies theclamp-closing finger-lever 23 and .rearwardly extending lever-arm 24 adapted. to be depressed automatically to close the clamp by the roll 25 at the front end of the clamp-closing lever 26 fulcrumed at 27 on the frame member 2 and actuated through the usual latch-pin connection 28 with the continuously running pulley29, as described in myfsaid reissued patent. The

other of the connected rockshaft sections 22, Fig. 2, carries the lever-arm 30 which the work relatively to the when ushed forwardly to the position shown in Fig, 2, effects the opening of the work-clamp andthe release of the work.

The work-holder is equipped with the usual clamp-spreading and unspreading sections are mounted as usual on the crossslide plate 34 which, in turn; is mounted on the longitudinal slide-frame 35.-

'The work-clamp derives the longitudinal components of its motion through the usual connection with a longitudinal feed-camgroove in the feed-wheel 17. The lateralcomponent of motion of the work-clamp is derived through the lever connection 36 with the lateral feed-cam groove 37 in the read-. ily removable controlling wheel 38 fixed on the rapid feedshaft 39 which. carries the bevel-gear 40 meshing with a similar gear.

. 41 .on the feed-wheel 17. The present feeding mechanism is of substantially the same construction as that shown in my said reissued patent, except that the main feedwheel of the present machine has no lateral feed-cam groove: the lateral feed'camve in the .controllin wheel being used Instead, throughout the uttonhole producing cycle. The connected feed-wheels 17 and 38 are driven at a slow speed during the sewing by means of suitable connections,

such as represented inmy said reissued.

patent, with the vertical shaft 11. Intermediate sewing operations the connected feed-wheels are driven at a higher speed bymeans of the ra id feed-shaft 39 which is connected throu an automatically controlled clutch-mec an sm with .the rapidfeed drive-shaft 42. and automatic clutch control are of substantially the construction represented in my copen ing application Serial No. 537,381, filed February 18, 1922, and comprise'the clutch 43, Fig. 6, and the continuously reciprocate ing clutch-operatin bars 44, 45. which are latched in their id e positions, Figs. 6 and 21, by means of the latches 46, 47. It will be understood, particularly from the disclosuresof my said copending application, Se-

rial No. 537,381. and my saidreissued pa-- tent, that the release of the latch 47 permits the bar to operate the clutch 43 to connect the shaft 39 to the rapid-feed driveshaft 42, thus throwing the rapid-feed mechanism into 0 eratibn, and release of the latch 46 permits the bar 44 to.operate the clutch to throw the rapid-feed .mecha-' nism out of operation. The throw-out latch 46 for the ra id-feed mechanism is connected to the ever 48, Fig. 21, which is operated by the tripping points 49 on the The rapid-feed drive inner face of the controlling wheel 38. The

rapid-feed throw-inlatch 47 is" connected to an arm 50 on.the rock-shaft 51. The shaft 51 carries arms. 52 and 53, Fig. 1, the former being depressed bya cam 54 on the usual clutch-disk 5.5 fast to the buttonhole cutter-shaft 56' "and/the latter being ele-'- vat-ed, as described in said copending appli 60,61, Fig. 4,'which are pivotally mounted .at 62 onthe travelling fulcrum-block 63;

the latter receiving its travelling movem'ents fromthe link connect on 64 with the cutter-advancing andretrac-ting cam 65 on the cutter-shaft 56. The cutter-shaft also Lcarriesthe usual cutter-lever closing cams 66,- 67. The disk 55011 the cutter-shaft con-' stitutes the driven member of the usua'lonerevolution. clutch device, the operation of which is controlled.- by 'movem'entofthe usual- C11l3te1-0l11t0l1 controlling lever 68 mounted on the vertical fulcrum-pin 69. As explained in my said copending-application Serial No. 537.381, clockwise movements of the lever 68. Fig.4, effects the coupling of' the cuttershaft'56 to the continuously rotating pulley 29 for one revolution after which the cutter-shaft is automatically uncoupled fro-m said pulley and brought to rest. The period of operation of the stitchforming mechanism is controlled through the stop-motion lever 58 and its usual lmk connection '70, Fig- 2, with, the lever 71 having-the follower, tooth 72 which bears upon the controlling wheel 38. When the tooth 72 is engaged by the cam incline 73, the stop-motion lever 58 is rocked clock- Wise, g- 2, to start the "'sti'tch forni g mechanism which continues in operation until the decli'vity 74 passes the tooth .72, whereupon the spring 75 restores the stop-motion lever to stopping position,;Fig. 2, and thereby arrests the action of the stitch-forming- -mechanism.

d The ,machine is preferably eduipped with means above the work for cutting and nipping the u iper thread at the end of the v sewln rod. The mechanism em lo ed is preferably constructed and operated sub.

stantially: in accordance with thediselosure of my Patent No..1,369,371-, of Feb. 22, 1921. The left-hand clamp-foot 20,, FigL-7, has pivotally mounted thereon the usual threadcutting and nippingblades 76, 77 which cooperate,-res ectively, with the ledger-blade 78 and slig tly resilient bar 79 to cut and nip the needle-thread. The blades 76 77 are operated by means of the usual rod to which the spring 81 is connected to pull it rearwardly or from full to dotted line position, Fig. 8, to carry the blades 76, 77, into cooperative relation with the ledger-blade 78 and bar 79 to sever and nip the needlethread. The rod 80 carries a latch-pin 82 which is engaged by the notched front end of the spring-pressed latch-lever 83 to hold the rod 80 in the position shown in full lines in Figs. 7 and 8. 'When the latch 83 is tripped, the upper thread cutter and nipper operates under the influence of the spring 81 to cut and nip the needle-thread.

Mechanism such as disclosed 'n my said Patent No. 1,369,371 is preferably provided for pushing the rod 80 forwardly to effect the release of the needle-thread during the sewing of the initial stitches and in time for the beginning end of said thread to be drawn down substantially flush with the work by the action of the stitch-forming instrumentalities.

the sewing, and the cam-actuated lever 85, 86, fulcrumed at 87, together with the endwise movable latch-pin 88 which is carried by the lever arm and is ejected by the cam 84 after the lever 85-, 86, has performed its function of setting the cutting and nipping blades 76, 77, in open position and thus re; leasing the beginning-needlerthread end.

The latch 83 is tripped by a connection with the sewing mechanism stop-motion device at the end of the sewing period, before the work-holder is shifted away from sewing position, by means ofthe vertical bar 89 which is pivotally connected at its upper end at 90 to the tension release lever 91. The bar 89 is guided in its motion by being slotted at 91 and confined to slide vertically by the headed screw 92 which passes freely through the slot 91 and into the bracket-arm 3. The bar 89 terminates at its lower end in a foot 93 beneath which the angular extension 94 of the latch-lever 83 is positioned at the end of the sewing period, Figs. 7 and .8. The upper thread tension device 95 and itsrelease lever 91 are of usual-construction represented in my Patent No. 1,346,102 of July 13, 1920; the lever 91 being operated from the tooth 57 of the stop motion device through the usual connections represented in my said reissued patent. Such connections include the link 96, lever 97, and three-armed latch-lever 98 mounted on the vertical link 99 connected at its upper end to the lever 91, all cooperating in the manner disclosed in my said reissued patent.

The cutter-shaft 56 has mounted thereon a cam 100 such as disclosed in my copending application Serial No. 558,644, filed May 5, 1922, which. actuates the T shaped lever 101, after the buttonhole has been cut, and

This mechanism comprises the cam 84, Fig. 1, which rotates continuously during as the cutter-levers are being'retracted, te

pushthe arm 32 of the clamp-spreading toggle device 31 forwardly and thus spread the work-clamp. The controlling wheel 38 carries a tooth 102, Fig. 2, which engages the follower 103 carried at the lower end of the lever 104 to rock the latter about its fixed pivot 105 and, through the link 106, actuate the rock-lever 107 and the push-rod 108 which latter rigidly carries the depending arm 109. The push-rod 108 engages the arm 30 of the work-clamp and moves the latter to the position shown in Fig.2 to open the work-clamp: At the same time the arm109 engages the freeend of the lever 33 and pushes it forwardly to unspread the work-clamp. The tooth 102 on the controlllng wheel engages the follower 103 just before the machine comes to rest with the parts in the positions shown in F ig. 2.

'VVhen sewin a fly-bar buttonhole under the usual conditions obtaining in prior buttonhole sewing machines-it is found that there is a tendency for the purl of the overlying stitches of the fly-bar'tostand intermediate the rows of needle-punctures,

wvhereas along the sides of the buttonhole the purl is drawn over to the edge of the buttonhole-slit or to the path of the curved needle. This variation in the position of the purl gives an undesirable appearance to the finished buttonhole. I have discovcred that by providing means for increasing the tension on the under thread while sewing the overlying fiy-bar stitches, the purl of such stitches may be drawn over to the curved needle-path and the desirable uniformity in the stitching preserved throughout the buttonhole.

Such means may conveniently comprise the fork 111 which is adapted to press directly upon one of the disks of the under thread tension device 115 and is mounted on the rock-shaft 112 journaled in the bear ing lugs 113 on the stationary supporting plate 114 for said under thread tension device. Secured to-the rock-shaft 112 is the arm 116 to the rearward end of which is secured the plate 117 having at its upper end a hole 118 for attachment of one end of the auxiliary tension spring 119, the other end of which is anchored to the adjustable pin 120. The plate 117 is forked at its lower end to embrace the necked front end of the push-pin 121 the rearward end of which bears upon the cam-wheel 122 fixed to the rapid-feed shaft 39. The pin 121' is slidably mounted in the bushing 123 secured to the machine frame. The major portion'of the periphery of the cam-wheel tween the points (1 and b, Fig. 20, the cut awayportion 124 of the cam'122 encounters the pm 121 and is of a depth such that the spring 119 is free to exert its predetermined pressure through the forlq 111 upon the tension disks 115, in addition to the pressure of the usual tension spring 125. 'Bythus automatically increasing the tension on the under thread a predetermined amount during the sewing of the overlyin fly-bar stitches, I have found that the purlwill be drawn over to the slit-stitch needle-punctures and the finished buttonhole will appear as in Fig. 20.

The under thread and cord-cutter is in many respects similar to that disclosed in my said copending-application Serial No. 523,056. The present mechanism is, however, simpler in construction and is actuated ries the follower stud 132 operating in the I stationary cam-slot 133. The cam-slot 133 is concentric .with the pivot 130 of the thread-cutter carrying lever 129 throughout the major portion of its length but is formed at its upper end with an offset'134 which operates to close .the scissors device after the latter reaches cutting position. The carrier-lever 129 is connected by the link 134 to the front end of the lever 135 fulcrumed at 136 to the bracket 137 on the machine bed. The rear end of the lever 135 carries a follower roll 138 enterin the cam-groove 139 in the cam 122 fixed to the rapid-feed shaft 39.

The scissors device is timed to operate after the Work-holder has been shifted rearwardly from sewing position a sufficient distance to effect the pulling of the last needleloop clear of the looper 8 and the pulling off of suflicient lengths of under thread and cord forthe beginning of a new sewing operation. When the scissors deviceisprojected to cutting position, the point of the ledger-blade grazes the .under'surface of the work close to the last stitch and enters between the work and the under thread and cord, in substantially the same manner described in my said copending application Serial No. 523,056. In the present lnstance, however, the needle-thread is cut above the work before the work-holder is shifted away from sewing position and the rearward motion of the workholder from sewing to thread-cuttingposition, pulls down the end of needle-thread and draws the last needle-loo clear of the under thread mechanism. ence no needle-loop gripper such as shown in my said copending application Serial No. 523,056 is required to clear the under thread mechanism of the last needle-loop.

. The present machine is preferably provided with a cord-nipper to arrest the feed of the cord during the sewing of the initial stitches, so that the initial stitches will he slid along the cord until the first stitch is even with the end of the cord, whereupon the nipper is opened to allow the cord to run from the supply. The cord-nipper may conveniently be made up in the form of a lever 140 pivoted at 141 to a lug 141 on the machinelbedf The lever=140 is formed between its ends with a cam-follower projection 14 2 adapted to be engaged by the cam sections 143 adj ustably secured in the circular groove 144 in the inner face of the controlling wheel 38 by screws 145 which pass through slots 146 in the controlling wheel 38. The lever 140 has slidably mounted transversely of its free end a pin 147, the outer end of which is backed up by the adjustable leaf spring 148 secured to the lever 140 by the holding screw 149 and adjusting screw 150. The free end of. the pin 147 is adapted to yieldingly nip the 'cord against the anvil surface 151 at a gap in the cord-guiding tube 152. One of the cam sections 143' o crates to close the cord-nipper when the initial stitches are being sewed and the other cam section 143 operates to close the nipper during theaction of the under thread-cutter to insure against overfeedin of the cord and to hold thecord against eflection during the cut-- ting operation.

Operation.

The construction and operation of various parts of the ,machine not hereinbefore referredto are not novel per se and are shown and described in my said prior patents. and copending applications.

The operator presses upon the finger-release 153 which through the usual connections described in In said copending application Serial No. 537,381, effects the release of the slide-pin-28 and the coupling for one revolutiononly of the clamp-closing lever 26 with the cam-groove 154, Fig. 5, in the continuously I running pulley 29. The

clamp-closing lever on its return movement "operates as usual through the bar 155 to trip the buttonhole cutter clutch-controlling lever 68 and effect the coupling of the cuttershaft 56 for one revolution only. with the continuously running pulley 29." The cutter shaft effects, inthe order named, the cutting of the buttonhole in the position shown in Fig. 14, the spreading of the buttonhole and the tripping of the atch 47 to couple the rapid-feed shaft 39 to its driver42 to efiect the rapid shift of the cut buttonhole. from Y buttonhole cutting position, Fig. 14, to sewing position, Fig.- 15. v p Just before 'the stitch-formmg mechanism is started the 'cord-nipper 147 is closed. As

the curved needle 7 makes its first up-stroke,

presented by ,the curved needle and as it ly from sewing position the lever '85, 86,

rises from its first descent upper threadis operated to open and set the 'nipplng and cutting blades; releasing the needle-thread end in time for it to be drawn down flush with the work.

As the initial stitches are with the under surface of the work as shown in.Fig. 16. When the initial stitches 157, Fig. 16, are even with the endof the cord, the .cord-nipper 147 is opened and the sewing proceeds in the usual manner around the buttonhole; the under thread tension being automatically increased by the action of the cam-controlled spring-pressed lever 111 when sewing the overlying stitches of the fly-bar to draw the purl over to. the curved needlepunctures.

When the sewing is completed the action of the stop-motion device releases the needlethread cuttin and nipping blades 76, 77 which nip an sever the needle-thread, as shown in Fig. 17, while the work-clamp is stillin sewing position.

The rapid-feed 's also tripped into action through the lifting of-the arm 53 by connection with'the sto ping tooth 57 and the work-clamp is rapid y shifted rearwardto thread-cutting This motion of the work clamp draws out fromthe needle-throat 18 safe lengths of underfthread and cord for the beginning of the next sewing operation and also draws the last needle-loop 158, Fig. 17 clear of the looper 8, as shown in Fig. 18. The cord is a ain nippedand the scissors device 126, 12 projected to operative position to sever the end of needle-thread the under thread and the cord close to the end of the buttonhole. As the scissors device 126, 127 is retracted the work-clamp is fed forwardly from thread-cutting to buttonhole cutting or'initial position, whereupon it is opened to release the work, Fig 19. When the work is removed, safe ends of cord and under thread remain sticking out of the needle-throat.

The invention is not to be understood as limited-to the particular form and arrangement of parts shown and described, as many modifications thereof within the scope of the appended claims will be obvious to those skilled in the art.

position, Fig. 18.

15. The

. formed the end 156 of under thread is drawn back flush Having thus set forth the nature of the invention, what I claim herein is 1. A buttonhole sewing machine having, in combination, stitch-forming devices 1ncluding needle and loop-taker mechanisms having a predetermined period of action, said loop-taker mechanism operating to retain a loop of needle-thread at the completion of the sewing period, a work-clamp,

means for relatively moving the stitchforming mechanism and work-clamp to sew around a buttonhole, means at the upper side of the work for cutting the needle-. thread automatically at the close of the sewing period,--means for thereafter relatively moving the stitch-forming mechanism-and work-holder to draw the end of needlethread through to the under side of the work and remove the retained needleloop. from the loop-taker, and means at the under side of the work timed to operate subsequent to said last-mentioned relative movement for severing the end of needlethread close to the last stitch.

2. A buttonhole sewing machine having, incombination, stitch-forming devices in cluding needle and loop-taker mechanisms having a predetermined period of action,

said loop-taker mechanism operating to retain a loop of needle-thread at the completion of the sewing period, a cord-guide, a work-clamp,.me'ans for relatively moving the stitch-forming mechanism and workclamp to sew around a buttonhole, the upper side of the work for cutting the needle-thread automaticall at the close of the sewing period, means or thereafter relatively moving the stitch-forming mechanism and work-holder to draw out a len h of cord and to draw the end of needle-t read through to the under side of the work and means at remove the retained needle-loop from the 7 loop-taker, and means below the work for severing the cord and needle-thread.

3. A. buttonhole sewing machine having, in combination, stitch-forming devices including up er thread mechanism and under thread mec anism, a work-holder, means for relatively moving the stitch-forming mechanism and work-holder during sewing periods to sew around buttonholes and for relatively separating the stitch-forming devices and work-holder intermediate sewing periods, means for severing the upper thread while the stitch-forming devices and workholder are relatively associated in sewing position, and means for severing the under thread while the stitch-forming devices and work-holder are relatively separated.

4. A buttonhole sewing machine having, in combination, stitch-forming devices including upper thread mechanism and under thread mechanism, a work-holder, means for moving the work-holder during sewing periods to sew around buttonholes and for removing the work-holder from sewing position intermediate sewing periods, means for severing the upper thread while the workholder occupies sewing position, and means for severing the under thread while the work-holder occupies a position removed from sewing position.

5. A buttonhole sewing machine having, in combination, stitch-forming devices comprising upper thread merhanism and under thread mechanism including a loop-taker upon which a loop of upper thread is retained below the work at the end of a sewing period, means for relatively moving the stitch-forming devices and Work-holder during sewing periods to sew around buttonholes and vfor relatively separating the stitch-forming devices and work-holder intermediate sewing periods, means at the upper side of the work for severing the up-.

per thread at the end of a sewing period while the'stitch-forming devices and work-- holder are relatively associated in sewing position, and means for severing the under thread and the end of upper thread below the work and close to the last stitch after the stitch-forming devices and work-holder have been relatively separated to draw the end of needle-thread through the work and clear of the loop-taker.

6. A buttonhole sewing machine having, in combination, stitch-forming devices including an upper straight depth-stitch needle and a lower curved slit-stitch needle, 3 buttonhole-cutter, a work-clamp occupying buttonhole cutting position at the beginning of a buttonhole-producing cycle, a thread-cutter,imeans for moving the workclamp from buttonhole cutting to sewing position and from' sewing position to a thread-cutting position more remote from the stitch-forming devices than the buttonhole cutting position of the workclamp and thence back to buttonhole cutting position, and means for operating said threadrcutter when the work-clamp is in said threadcutting position.

7. A buttonhole sewing machine having, in ombination, stitch-forming devices, a work-clamp, a buttonhole cutter, a threadcutter, said work-clamp prior to sewing oocupying a buttonholecutting position re moved from the stitch-forming devices, means for operating the buttonhole cutter prior to-sewing, feed-cam means, feed-cam driving means'and connections for shifting the work holder from buttonhole cutting to sewing position, thence to sew around the buttonhole, thence from sewing position through buttonhole cutting position to a thread-cutting position more remote from sewing position, and means for operating the thread-cutter while the work-clamp is in said thread-cutting position.

8. A buttonhole sewing machine having,

. driving means and connections in combination, stitch-forming devices, a

driving meansand connections for shifting the work-holder from buttonhole cutting to sewing position,'thence .to sew around the buttonhole, thence from sewing position through buttonhole cutting position to a thread-cutting position more remote from sewing position and then back to button- .hole cutting position, and means connected to be operated by the teed-cam driving means for operating the thread-cutter while the work-clamp is in said thread-cutting position.

9. A buttonhole, sewing machine having, in combination, stitch-forming devices, a

work-clamp, a buttonhole cutter, a threadcutter, said work-clamp prior to sewing occupying a buttonhole cutting position removed from the stitch-forming devices, means for operating the buttonhole cutter prior to sewing, feed-cam means, feed-cam for shifting the workholder from buttonhole cutting to sewing position, thence to sew around the buttonhole, thence from sewing position thread-cutting position more remote from sewing position, and thenback to buttonhole cutting position, and a thread-cutter operating cam actuated. by the feed-cam driving means and timed to operate the thread-cutter while the work-clamp is in said thread-cutting position.

10. A buttonhole sewing machine having, in combination, stitch-forming devices including upper thread mechanism and under through buttonhole cutting position to a der thread cutters having spaced threadcutting positions, and means for moving, the work from one thread-cutting position to the other. V 12. In a sewing machine, a plurality of separated and differentially time automatic thread-cutters, and means for moving the workafter one thread-cutting operation to a position for action of the other threadcutter.

13. In a sewing machine, a plurality of differentially timed automatic thread-cutters separated in a direction parallel with the plane of the work, and automatic means for moving the work in its own plane from one positions, and means for relatively moving the stitch-forming mechanism and workclamp to sew about a buttonhole and for moving the work-clamp from upper threadcutting position to under thread-cutting position. v

15. In a sewing machine, a plurality of differentially timed automatic thread-cutters having laterally: spaced thread-cutting positions, and automatic, means acting between thread-cuttingoperations to move the work from one thread-cutting position' to the other.

16. In a sewing'machine, stitch-forming devices including upper thread mechanism and under thread mechanism, a stop-motion device for controlling the period of action of the stitch-forming devices, upper and under thread-cutters, means actuated by the stop-motion device for timing the operation of the .upper thread-cutter, and means thrown into operation by the stop-motion device for subsequently operating the under thread-cutter.

In testimony whereof, I have signed my name to this specification.

EDWARD B. ALLEN. 

